1. Field of the Invention
The field of the present invention is air filter attachment and detachment structures in air conditioning devices used for a motor vehicle, wherein the air conditioning device has an air passage means that is disposed inside an instrument panel having a glove box opposed to a compartment of the motor vehicle, the air passage means being located forwardly of the glove box in a vehicle body of the motor vehicle and extending laterally of the vehicle body, and wherein an air filter of a square plate shape is attached to and detached from the air passage means through an air filter attachment and detachment slit provided in the air passage means.
2. Description of the Prior Art
An air filter provided in an air passage means of an air conditioning device for a motor vehicle has an element made of electrified fiber material and operates to purify the air, that is being introduced into the compartment, by causing dust in the air to be absorbed onto the element with the function of static electricity.
The air passage means of such air conditioning device is, however, disposed generally at a lower portion of an instrument panel that is located forwardly of an assistant driver's seat in the vehicle body and a glove box is mounted on a side of the air passage means close to the compartment. Therefore, the replacement of the air filter must be conducted from below the instrument panel so as not to interfere with the glove box. The distance between the lower surface of the instrument panel and the floor is, however, small and moreover, a toe board is provided continuously from the floor so as to rise upwardly at a forward inclination relative to the floor, so that it is difficult to attach and detach the air filter from below the instrument panel without any special contrivance.
It has, therefore, been proposed conventionally to construct the air filter into a one 01 that is foldable at a plurality of hinge means 01.sub.1, as shown in FIGS. 9 and 10. This air filter 01 is attached to and detached from an air filter attachment and detachment slit 06.sub.1 formed at a lower surface of air passage means 06 inside an instrument panel 05 while being passed through a space defined among a glove box 02, a floor 03 and a toe board 04.
As another countermeasure, as shown in FIG. 11, an air filter 01 having notches 01.sub.2, 01.sub.3, 01.sub.4 formed at its outer periphery has been proposed and this air filter 01 is attached to and detached from an air filter attachment and detachment slit 06.sub.1 provided at a lower surface of air passage means 06 while being rotated.
In the case of the first mentioned conventional measure, however, the provision of a plurality of hinge means 01.sub.1 not only makes the structure complicated and raises the production cost but also reduces the effective area of the said element of the air filter 01, leading to an increase in resistance against the air passage and a reduction in the dust trapping and collecting effect.
In the latter measure, the provision of the notches 01.sub.2, 01.sub.3, 01.sub.4 reduces the effective area of the element of the air filter 01 thereby to increase the resistance against the air passage and lower the trapping effect but also reduces the yield for the element of the air filter 01 at the time of manufacturing. Moreover, in both the measures, it is difficult to visually recognize the air filter attachment and detachment slit 06.sub.1 of the air passage means 06 from the side of the compartment so that there is a problem in the efficiency in performing the attaching and detaching operation of the air filter 01.
The present invention has been proposed in view of these circumstances and an object thereof is to facilitate the operation of attaching and detaching an air filter of a square plate shape to and from a slit formed at an air passage means of an air conditioning device.